Phytochemical Profile and Evaluation of the Allelopathic Effect of the Aqueous Extract of Fimbristylis miliacea (L.) Vahl (Cyperaceae)

The allelopathic potential of some plant species has been scientifically proven over the years. The use of such natural compounds with phytotoxic activity is an alternative to synthetic herbicides. Thus, this research aims to analyze the phytochemical profile and the allelopathic effect of aqueous extracts of Fimbristylis miliacea (L.) Vahl. The allelopathic potential was evaluated by germination bioassays using seeds from two receptor species (Lactuca sativa L. and Emilia fosbergii Nicolson) and seven concentrations of aqueous extracts of F. miliacea aerial and underground parts in triplicate. The variables evaluated were germination (G) and germination speed index (GSI). The data obtained were submitted to F test and the averages to regression analysis. In addition, phytochemical analyses were performed to analyze possible allelochemicals present in aqueous extracts of F. miliacea through phytochemical screening and by high performance liquid chromatography (HPLC). The aqueous extracts of aerial and underground parts of F. miliacea inhibit the germination of E. fosbergii seeds at all concentrations analyzed (0.94, 1.87, 3.75, 7.5, 15 and 30%). However, the same extracts do not show any effects when evaluated in L. sativa seeds. The aqueous extract of F. miliacea shows important chemical constituents (gallic acid, chlorogenic acid, rutin, luteolin, apigenin, acacetin, and alkaloids) that can be directly related to the allelopathic effects observed in E. fosbergii seeds.